In a motor vehicle, a four-wheel drive system or an all-wheel drive system can be selectively activated by a clutch. The clutch can be part of a power transfer unit (PTU) for connecting a power source to a secondary drive shaft when it is desired to deliver power to the secondary drive shaft. It is known that such a clutch can be a dog clutch. Dog clutches are prone to teeth clash or blocking. It is also known that such a clutch can be a wet clutch in a differential. Pressurized fluid must be continuously supplied to keep the clutches in a closed mode, adding to the power usage associated with usage of the clutch.
Such a clutch can also be a wedge clutch. A wedge clutch can include an inner race connected to an input or output shaft, and an outer race connected to the other of the shafts. A wedge plate can be radially disposed between the inner and outer races and be configured to engage the inner and outer races when the clutch is locked to transmit power from the input shaft to the output shaft.